What's "something"? It might help if we knew what you were trying to do with that "something"
Be sure to check ownership:
And change ownership to the user you want to actually be that owner:
chown username file
And finally, read up on the man page of chmod, you don't HAVE to use the numeric representations of the permissions. If you are confused, there's the easy way out:
chmod a+rw file
Will give everyone (a+) read and write (rw) permissions.